1. Field of Invention
This invention pertains generally to the monitoring of parameters in bioprocesses and, more particularly, to an aseptic manifold and probe assembly for use on a vessel in which a bioprocess is carried out.
2. Related Art
In bioprocessing, parameters such as conductivity, pH, temperature, oxidation reduction potential, O2, CO2, and optical density are commonly monitored with probes which are inserted into the vessels in which the processes are carried out.
A typical probe of the type currently in use and a typical installation of such a probe are illustrated in FIGS. 1-3. The probe 21 has an elongated body 22 with a dome-shaped tip 23 at one end, an enlarged threaded section 24 toward the other end, and an electrical connector 26 at the end opposite the tip. The probe is mounted in an adapter 27 which is mounted in a fitting 28 welded to the side wall 29 of a vessel, with the tip of the probe immersed in the fluid in the vessel.
The adapter has an axially extending bore 31 with an internally threaded section 32 corresponding to the threaded section of the probe. When the probe is threaded into the adapter, the body of the probe extends through the bore and beyond the distal end of the adapter, with O-rings 33, 33 providing a seal between the adapter and the probe. The adapter also has a radially extending external flange 34 which is engaged by a retaining nut 36 to secure the adapter and the probe to the fitting. An O-ring 37 provides a seal between the adapter and the fitting.
This installation has a number of limitations and disadvantages. The port fitting is welded on both sides of the vessel wall and is inclined at an angle of approximately 15 degrees to the horizontal. Both welds must be ground and polished, and the orientation of the port must be maintained. These are labor intensive operations which must be repeated for each probe that is used. Moreover, during the welding operations, the fittings and vessel wall can overheat and warp, and the fitting threads can be damaged. With inclined fittings and O-ring seals, the gasket seats are set in such a way that sterilization can be difficult, and visual inspection of the seal areas to ensure they are clean and free of residue is almost impossible.